We assessed visual recognition in monkeys after early damage to either the medial temporal limbic region or to cortical visual area TE, both of which are known to be critical for this mnemonic ability in adults. The results indicated greater functional sparing after neonatal cortical than after neonatal limbic removals, suggesting that, during infancy, visual recognition functions are widely distributed throughout many visual cortical areas and that they become critically dependent on (i.e. localized to) area TE only after cortical maturation. Further evidence that functions are widely distributed at birth due to cortical immaturity comes from our studies on the development of rule learning ability in infant monkeys. Whereas the ventral prefrontal cortex is critical for this function in infant monkeys, it is not critical in infants. Limbic structures, by contrast, are even more critical for this function in infant monkeys than in adults. Similarly, limbic structures appear to be even more critical in infancy than in adulthood for the development of socioemotional behavior. Neonatal limbic lesions yield socioemotional disturbances similar to those described in autistic children, whereas the disturbances produced by the same damage to the mature brain are significantly less severe.